微信授权

项目场景：微信授权

问题描述：根据code值获取手机号

步骤一：
String result = “”;
WxMaJscode2SessionResult session = null;
try {
session = wxMaService.getUserService().getSessionInfo(dto.getCode());//code是前端给的code，可以配置多个小程序
} catch (WxErrorException e) {
throw new RuntimeException(“获取微信 Session 异常”);
}
String openId = session.getOpenid();
String sessionKey = session.getSessionKey();

	String decrypt = WXCore.decrypt(dto.getAppid(), dto.getEncryptedData(), sessionKey, dto.getIv());
 	JSONObject jsonObject = JSON.parseObject(decrypt);
    String phoneNumber1 = jsonObject.getString("phoneNumber");//获取微信授权的手机号

步骤二：
try {
AES aes = new AES();
result = aes.decryptNew(encryptedData, sessionKey, iv);
} catch (Exception e) {
result = “”;
e.printStackTrace();
}

步骤三： AES 工具
public byte[] decrypt(byte[] content, byte[] keyByte, byte[] ivByte) throws InvalidAlgorithmParameterException {
initialize();
try {
Cipher cipher = Cipher.getInstance(“AES/CBC/PKCS7Padding”);
SecretKeySpec sKeySpec = new SecretKeySpec(keyByte, “AES”);
cipher.init(Cipher.DECRYPT_MODE, sKeySpec, generateIV(ivByte));// 初始化
byte[] result = cipher.doFinal(content);
return result;
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (NoSuchPaddingException e) {
e.printStackTrace();
} catch (InvalidKeyException e) {
e.printStackTrace();
} catch (IllegalBlockSizeException e) {
e.printStackTrace();
} catch (BadPaddingException e) {
e.printStackTrace();
} catch (NoSuchProviderException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}

public static void initialize() {
    if (initialized) {
        return;
    }
    Security.addProvider(new BouncyCastleProvider());
    initialized = true;
}

// 生成iv
public static AlgorithmParameters generateIV(byte[] iv) throws Exception {
    AlgorithmParameters params = AlgorithmParameters.getInstance("AES");
    params.init(new IvParameterSpec(iv));
    return params;
}
public  String decryptNew(String encryptedData, String sessionKey, String iv)  {
    String result = "";
    // 被加密的数据
    byte[] dataByte = Base64.decodeBase64(encryptedData);
    // 加密秘钥
    byte[] keyByte = Base64.decodeBase64(sessionKey);
    // 偏移量
    byte[] ivByte = Base64.decodeBase64(iv);
    try {
        // 如果**不足16位，那么就补足. 这个if 中的内容很重要
        int base = 16;
        if (keyByte.length % base != 0) {
            int groups = keyByte.length / base + (keyByte.length % base != 0 ? 1 : 0);
            byte[] temp = new byte[groups * base];
            Arrays.fill(temp, (byte) 0);
            System.arraycopy(keyByte, 0, temp, 0, keyByte.length);
            keyByte = temp;
        }
        // 初始化
        Security.addProvider(new BouncyCastleProvider());
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding", "BC");
        SecretKeySpec spec = new SecretKeySpec(keyByte, "AES");
        AlgorithmParameters parameters = AlgorithmParameters.getInstance("AES");
        parameters.init(new IvParameterSpec(ivByte));
        // 初始化
        cipher.init(Cipher.DECRYPT_MODE, spec, parameters);
        byte[] resultByte = cipher.doFinal(dataByte);
        if (null != resultByte && resultByte.length > 0) {
            result = new String(resultByte, "UTF-8");
        }
    } catch (NoSuchAlgorithmException e) {
        log.error(e.getMessage(), e);
    } catch (NoSuchPaddingException e) {
        log.error(e.getMessage(), e);
    } catch (InvalidParameterSpecException e) {
        log.error(e.getMessage(), e);
    } catch (IllegalBlockSizeException e) {
        log.error(e.getMessage(), e);
    } catch (BadPaddingException e) {
        log.error(e.getMessage(), e);
    } catch (UnsupportedEncodingException e) {
        log.error(e.getMessage(), e);
    } catch (InvalidKeyException e) {
        log.error(e.getMessage(), e);
    } catch (InvalidAlgorithmParameterException e) {
        log.error(e.getMessage(), e);
    } catch (NoSuchProviderException e) {
        log.error(e.getMessage(), e);
    }
    return result;
}

步骤四： WxPKCS7Encoder工具
private static final Charset CHARSET = Charset.forName(“utf-8”);
private static final int BLOCK_SIZE = 32;

/**
 * 获得对明文进行补位填充的字节.
 *
 * @param count
 *            需要进行填充补位操作的明文字节个数
 * @return 补齐用的字节数组
 */
public static byte[] encode(int count) {
    // 计算需要填充的位数
    int amountToPad = BLOCK_SIZE - (count % BLOCK_SIZE);
    if (amountToPad == 0) {
        amountToPad = BLOCK_SIZE;
    }
    // 获得补位所用的字符
    char padChr = chr(amountToPad);
    String tmp = new String();
    for (int index = 0; index < amountToPad; index++) {
        tmp += padChr;
    }
    return tmp.getBytes(CHARSET);
}

/**
 * 删除解密后明文的补位字符
 *
 * @param decrypted
 *            解密后的明文
 * @return 删除补位字符后的明文
 */
public static byte[] decode(byte[] decrypted) {
    int pad = decrypted[decrypted.length - 1];
    if (pad < 1 || pad > 32) {
        pad = 0;
    }
    return Arrays.copyOfRange(decrypted, 0, decrypted.length - pad);
}

/**
 * 将数字转化成ASCII码对应的字符，用于对明文进行补码
 *
 * @param a
 *            需要转化的数字
 * @return 转化得到的字符
 */
public static char chr(int a) {
    byte target = (byte) (a & 0xFF);
    return (char) target;
}